Nervous Transmission

Tasaki, Ichiji; Thomas, Charles C.

doi:10.1097/00007611-195412000-00031

Cited by 48 publications

(65 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…There is about a 2-3-fold difference between the threshold at the node directly under the electrode and the extrapolated threshold for firing a neighbouring node using the electrode located at the original node. Similar isolation of nodes in fibres from desheathed frog nerves was found using ring electrodes 1 cm apart (Lussier & Rushton, 1952) and using Tasaki's ridge-insulator technique (Tasaki, 1939(Tasaki, , 1953. Bostock et al (1983), using tripolar electrodes with varying separations, found an isolation in liquid paraffin of 10 to 1 in single fibres from rat ventral roots.…”

Section: Degree Ofsimilarity Among Nodessupporting

confidence: 53%

“…A given node generates currents which conduct through passive internodal regions to trigger action potentials at the next node (Huxley & Stiimpfli, 1949;Tasaki, 1953). Measurements of firing threshold in single axons from human median nerve (Bergmans, 1968a, c) and frog sciatic nerve (Raymond, 1979) have revealed that impulse activity in a fibre is followed by a characteristic sequence of oscillatory transients in the firing threshold.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of the after‐effects of impulse conduction on threshold at nodes of Ranvier along single frog sciatic axons.

Carley

Raymond

1987

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Single axons were teased from the distal end of whole frog sciatic nerve and impulses were recorded with a suction electrode. The whole nerve trunk was stimulated using a gross electrode that was slowly moved for several centimetres along the length of the nerve. The threshold for initiation of an action potential showed periodic minima which were interpreted as the location of nodes of Ranvier.2. Internodal distances were uniform along individual fibres but differed among fibres having matching conduction velocities, suggesting that other individuating characteristics are also important in determining the spacing of nodes.3. A standard protocol was used to measure the activity dependence of threshold. Nodes along any given fibre were found to be alike in the dependence of threshold on impulse activity. Both the superexcitable phase and the depressed phase of the after-effects of impulse activity were similar for successive nodes. This suggests that the activity dependence of an unbranched length of axon can be well characterized by looking at any one of its nodes.4. Comparison of nodes from different axons showed large variations in activity dependence. Depressibility, denoting the relative tendency of an axon to show depression, was quantified either as the initial rate of rise in threshold (percentage increase/min) following the onset of repetitive stimulation or as the total rise in threshold (percentage increase) after 5 min of exposure to a standardized rate of repetitive stimulation. By either measure depressibility differed among axons more than it differed among nodes from a single axon.5. Superexcitability following single impulses was measured in the absence of depression. Axons exhibiting a larger decrease in threshold during the superexcitable phase also tended to show larger depressions relative to other axons when stimulated at a given rate.6. There was little correlation between conduction velocity and the magnitude of either the depressed phase or the superexcitable phase within the population of fibres studied. This suggests that axon diameter alone (as indicated by conduction velocity)

show abstract

Section: Degree Ofsimilarity Among Nodessupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Comparison of the after‐effects of impulse conduction on threshold at nodes of Ranvier along single frog sciatic axons.

Carley

Raymond

1987

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…In this connexion Tasaki has estimated that conduction of the second impulse should cease at a time when, during the recovery period, the amplitude of the second spike is below 40 % of normal (Tasaki, 1953).…”

Section: Nerve Impulses and Conduction Velocitiesmentioning

confidence: 99%

The influence of diameter of medullated nerve fibres of cats on the rising and falling phases of the spike and its recovery

Paintal¹

1966

The Journal of Physiology

144

View full text Add to dashboard Cite

SUMMARY1. The relation of conduction velocity, i.e. fibre diameter (Hursh, 1939a) to certain temporal dimensions of the nerve impulse recorded monophasically was studied in medullated fibres of cats in vivo at temperatures mostly ranging between 21 and 370 C.2. Contrary to existing belief, it was demonstrated unequivocally that spike duration varies inversely with the conduction velocities of the fibres; so also the durations of the rising and the falling phases (rise-time and fall-time) of the impulse. The fall-time is linearly related to conduction velocity at all recorded temperatures. The rise-time varies steeply with conduction velocity at the lower levels of conduction rate, and very gradually at the higher conduction rates.3. The spike duration of preganglionic sympathetic fibres is identical with that of somatic medullated fibres with similar conduction velocities. There is therefore little justification for classifying them separately as so-called B fibres.4. The rate of recovery of spike amplitude following a preceding impulse also varies inversely with conduction velocity, and in the same manner as the absolute refractory period (ARP). In fact the relation of time for 40 % recovery of spike amplitude to conduction velocity is identical with the relation of conduction velocity to ARP. The Qlo for 40 % recovery of spike amplitude is 4*7 between 13 and 290 C.5. Rise-time increases exponentially with fall in temperature in all medullated fibres, fast (say 64 m/sec) and slow (say 16 m/sec), the Qlo being 2-5. Fall-time varies exponentially with temperature in slow fibres (Qlo = 3.5); in fast fibres it varies linearly. The Qlo for spike duration is the same in all fibres between 27 and 370 C only, its value being about 3-4. Below 270 C the Qlo depends on the conduction velocity of the fibres.Only in slow fibres does spike duration tend to vary exponentially with temperature.6. Only abortive spikes are generated during the interval between the end of a preceding spike and the end of the ARP which is about 1i times spike duration in fast fibres and about twice spike duration in slow fibres.

show abstract

“…The time course of the response of tetanized nerve fibers is similar to the time course of the response of cardiac muscle fibers (18), of Purkinje fibers (3), of crustacean muscle fibers treated with TEAC (4), and of nerve fibers treated with NaC1 (hypertonic), sinomenine, heroine, brucine, emetine (14), or azide (unpublished experiments).…”

Section: Discussionmentioning

confidence: 54%

“…Single nerve fiber responses were recorded with three arrangements of the "bridge insulator" method (14). The nerve innervating the semitendinous or sartorins muscle of the toad (Bufo ~rinus) was used.…”

Section: Methodsmentioning

confidence: 99%

Changes in the Duration of the Electric Response of Single Nerve Fibers Following Repetitive Stimulation

Spyropoulos

1956

The Journal of General Physiology

View full text Add to dashboard Cite

Single nerve fibers were isolated from the nerve innervating the sartorius or semitendinosus muscle of the toad (Bufo marinus). Single nerve fiber responses were recorded with three arrangements of the "bridge insulator" method. During stimulation at 50 to 150 pulses per second for 20 to 140 minutes the spike duration was progressively increased. After tetanization the spike duration usually continued to increase at a more rapid rate. Within 5 to 60 minutes further prolongation stopped and within 1 to 10 hours the spike duration was normal. The duration of the response of tetanized fibers was from 2.5 to more than 10 times the spike duration of untetanized fibers. Prolongation was observed in nerve fibers isolated from nerves tetanized in vivo.

show abstract

Nervous Transmission

Cited by 48 publications

References 0 publications

Comparison of the after‐effects of impulse conduction on threshold at nodes of Ranvier along single frog sciatic axons.

Comparison of the after‐effects of impulse conduction on threshold at nodes of Ranvier along single frog sciatic axons.

The influence of diameter of medullated nerve fibres of cats on the rising and falling phases of the spike and its recovery

Changes in the Duration of the Electric Response of Single Nerve Fibers Following Repetitive Stimulation

Contact Info

Product

Resources

About